"What's
in a name? That which we call a rose . . . By any other name
would smell as sweet." Unless the name happens to end
with a Singh or Kaur.

Wikipedia
entry describes the naming patterns using Singh and Kaur as
last names

Sometimes,
Singh is used as a middle name after the given name and
followed by the caste/clan/family name. For example, "Chandan
Singh Kumar", "vikram singh pratap", "Natwar
Singh", "hanuman Singh Khanna" etc (Pattern:
1. First name, 2. Singh, 3. family/clan name).

One
usage is the given name and Singh as the surname. For example,
"Maharana SIngh", "Kishan Singh", "Raghubir
Singh", "Mohan Singh" etc.

The latter
seems to be the cause of concern among those awaiting immigration
to Canada. Here is a recent press release from Immigration
Canada:

The
Honourable Diane Finley, Minister of Citizenship and Immigration
(CIC), issued the following statement today regarding CIC’s
longstanding policy which asks permanent resident applicants
with the surname "Singh" and "Kaur" to provide an additional
surname on their application.

"It
has been brought to my attention that a letter was sent
to an applicant telling him that unless he provided an additional
surname in addition to other documentation, his application
for permanent residence may not be processed. This letter
does not reflect the policy of Canada’s New Government,
and I can assure you I have directed the department to ensure
that this type of erroneous letter is not sent out again.

"The
practice of asking applicants with the surname "Singh" and
"Kaur" to provide an additional surname was designed to
help identify and differentiate applicants who shared the
same first and last names. Providing an additional surname
is entirely voluntary. The policy of Canada’s New Government
is that applicants with the surnames "Singh" or "Kaur" may,
but are not required to, provide an additional surname.
No application for permanent residence will be rejected
if the applicant chooses not to provide an additional surname."
Wikipedia begins by describing Singh is an ancient Indian
vedic name meaning "Lion", dating back over 2000 years to
ancient India. It is used by Hindus and Sikhs. It was originally
a Rajput surname, but is now found in all varnas throughout
India.

This problem
may be an issue for prospective immigrants to the US
too. [FBI Name Check Cited In Naturalization Delays: Washington
Post]

This brings
home an interesting aspect of Singh and Kaur as last names
common among sikhs, but also many other hindus of Indian Origin.
For instance, wikipedia
says "Singh is an ancient Indian vedic name meaning
"Lion", dating back over 2000 years to ancient India.
It is used by Hindus and Sikhs. It was originally a Rajput
surname, but is now found in all varnas throughout India."

More FAQ
on Last names as Singh and Kaur: Why do Sikh men have the
last name Singh and all women, have the last name Kaur? [Ref:
RealSikhism

Singh
means a lion and Kaur means a princess. In Sikhism these titles
eliminate discrimination based on “family name” (which denotes
a specific caste) and reinforces that all Sikhs are sovereigns
under God.

This
tradition started because through the last name one could
distinguish what caste you are from. Just by hearing the last
name they would say, “Oh, you are the lowest” or “Oh, you
are the middle” or “Oh, you are from high class”. Thus the
Guru eliminated the last name from all the Sikhs so that no
one could tell the caste and achieved equality for all Sikhs.
He gave Singh as a last name to all the Sikh men and Kaur
to all the Sikh women. Women were not treated as equals before
the time of the Gurus, and so to ensure equality, a movement
for women’s liberation was started five hundred years ago
with the Sikh faith. The Guru said, “You are my beloved princesses,
my daughters. You must be respected. How can this world be
without you?” He admonished men for being rude and bad to
women. He said, “Without women this world cannot be. So give
them rights, give them equal respect.” So the Sikh faith says
that you must respect women. Normally, when a woman would
get married, she would take the last name of the family she
went to. Since Guru eliminated the name, he said, “You don’t
have to take anybody else's name. You are an individual, you
are a princess, and you keep Kaur as your last name.” It gave
women a lot of self-respect.